372 On Certain Bacteria from the Air of New York City. 



Bioloffij. Gelatin quickly liquefied, milk coaj!;ulated, but usually not till after 

 some time; nitrate partly reduced, not completely; lactose-litmus not 

 reddened. Growth on agar translucent white with a marked tendency 

 to spread over the surface in a very thin layer. 



96. Bacillus ocliraceus (Zimmermann). 

 Occurrence. From Krai's laboratory. 



3Iorpholo(jy. Slender bacilli, .4X1-3/", singly or in chains separated by spaces; 



not motile. 

 Biology. As in No. 95, but the growth is very different, being opaque, orange 



yellow streaked with white, not spreading widely. 

 Remarks. This species is said to be motile, " slow and serpentine, " but my 



cultures did not show it. 



97. Bacillus prodigiosus (Eherenberg). 

 Occurrence. From the college collection. 



Morpholngji. Small rounded bacilli, .5X1/', mostly singly, actively motile. 

 Biology. Gelatin quickly liquefied, nitrate completely reduced; lactose-litmus 



reddened. Tlie ciiltures on agar were viscid. 

 Jiemarks. This species is said to form gas in presence of sugar, Init my cultures 



did not, and it seems more likely that this species and B. rosncnts mcfnl- 



loidea (No. 11.3) have been confounded, as they are closely alike except 



for the gas formation. 



98. Bacillus indicus (Koch). 

 Occurrence. " Bacillus indicus ruber," from the college collection. 

 3IoTpUology and biology. As in No. 97 except that the growth is not viscid. 



(Compare Nos. 113 and 114.) 

 Remarks. The culture before me has become white. This form is not to lie 



distinguished from the white variety of No. 97. I do not know whether 



its chromogenic form is the same or not. 



■'o'- 



99. Bacillus violaceus laureutius (Jordan). 



Occurrence. (1) " Bacillus violaceus," from Krai's laboratory. (2) "Mi- 

 crococcus violaceous," from Krai's laboratory. 



Morphology. Small bacilli, .5X1 Z', singly or in long chains, motile. 



Biology. Gelatin quickly liquefied, milk coagulated, nitrate completely re- 

 duced and rapidly ; lactose-litmus made blue, rosolic acid not changed ; 

 forms indol; scarcely any growth on potato. 



Remarks. Tliis can not be B. violaceus Frankland, as it was not oljserved to 

 form spores. It differs from B. lividus Plagge and Proskaner in li(juefy- 

 ing gelatin rapidly. It differs from B. jacinthus Zopf, in coagulating 

 milk, while the gi'owth is not tough, but agrees with it in reducing ni- 

 trate quicklj-. It differs from £. violaceux laureutius .Jordan in reducing 

 nitrate quickly, in producing the violet color in ordinary broth and in 

 not growing on potato; but I have not felt justified to consider these dif- 

 ferences as specific. 



